John Bean writes – “Take a look at two new presentations on our website. The common theme is that there is lot more going on than meets the eye. With the Van de Graaff generator, the expected electronic circuits are all missing and it instead depends on differences between materials . . . along with a dirty trick played on some gullible electrons. And for the CD/DVD, although everyone knows that it involves a laser focusing on the disk, it turns out you must use some incredibly clever optical tricks to maintain focus as the wavy surface of the disk spins round and round … – Van de Graaff generator & CD/DVD drives.